Assemblies, such as automotive vehicles, often utilize various types of selectively movable and/or selectively rotatable members and require that these members or "shafts" be operatively coupled in a manner which allows the created torque or rotational energy to be communicated and/or transmitted between the coupled members and/or to other portions resident within the assembly.
For example and without limitation, an intermediate shaft is typically mounted within an automobile and is coupled to and transfers torque between the steering column and the gear shaft. Particularly, the selective rotational energy of the steering column is transferred through the intermediate shaft to the gear shaft and the wheel suspension assembly, thereby allowing the vehicle to be selectively steered.
Typically, the intermediate shaft comprises and/or represents a telescoping shaft which allows the steering column and gear shaft to be axially compliant (i.e., to selectively move "toward and away" from each other). This compliance compensates for the relative movement between the vehicle body and vehicle frame which occurs as the car is driven; absorbs and/or reduces the transmission of vibrations and/or energy generated from the vehicle's wheel suspension assembly, to the steering column; and allows the steering column to substantially and desirably "collapse" in the event of a collision or accident, thereby preventing and/or substantially reducing the probability of injury to the driver.
Another example of an "axially compliant" vehicle assembly for coupling two selectively rotatable shafts or members is a driveshaft. Particularly, a vehicle driveshaft is typically and operatively coupled to a transmission assembly and to a differential assembly and selectively transfers the transmission produced torque to the differential, thereby causing the vehicle wheels to desirably rotate. A vehicle driveshaft utilizes and/or comprises a telescoping member which selectively expands, thereby allowing the driveshaft to compensate for the relative movement between the differential and the transmission.
Although these prior assemblies effectively transmit torque between the two coupled members or shafts while allowing the members to reciprocally move with respect to each other (e.g., each of the coupled members may selectively and independently move "toward and away" from the other), they suffer from some drawbacks.
For example and without limitation, these prior telescoping members generate a relatively large amount of friction, which combined with their relatively short engagement lengths, hinders and/or slows the desired telescoping movement, generates undesirable inertial movements, and creates excessive wear and fatigue to and of the telescoping members, thereby resulting in failure, "frictional lock-up", "shock loading", and/or diminished performance. These telescoping members are further relatively highly susceptible to contamination from dirt, dust, moisture and other environmental materials, which become lodged between telescoping members.
Such contamination further causes performance degradation and/or failure of the telescoping members, thereby undesirably allowing vibrations and/or movement to be readily transferred between the coupled components, such as between the wheel suspension assembly and the steering column or between the transmission and the differential.
There is therefore a need to provide an assembly for coupling two members or shafts which overcomes at least some of the various and previously delineated drawbacks of prior coupling assemblies; which allows torque and rotational energy to be efficiently transmitted between the two coupled members or shafts; which allows each of the members or shafts to selectively and reciprocally move with respect to the other; which substantially eliminates and/or reduces frictional losses and the transfer of vibrational energy by and between the coupled members or shafts; and which allows the members or shafts to be moveable in a variety of orientations and/or positions.